The invention relates to a method for fabricating a microfluidic component comprising at least one microchannel delineated by bottom and top walls and two opposite side walls, a method comprising:                formation, in a surface of a substrate, of the bottom wall and of the two opposite side walls of said microchannel,        formation of nanostructures filling said microchannel by in situ growth from a metallic catalyst layer deposited on the opposite side walls and on the bottom wall of said microchannel,        and formation of the top wall of said microchannel by positioning a cover on said surface of the substrate and sealing said cover on said surface.        